"Sword and Fairy IV" is a popular Xianxia drama that has been broadcast recently, starring Ju Jingyi and Chen Zheyuan, mainly telling the story of Yun Tianhe, Han Lingsha, Murong Ziying and Liu Mengli and other people looking for the past, cultivating immortals, and protecting the common people. At the beginning of the story, it was explained that nineteen years ago, the Qionghua faction created the Xihe Sword and the Wangshu Sword, under the banner of destroying demons, in fact, they wanted to use these two swords to help them ascend to immortals.
At that time, the host of Wangshu Sword was Shuyu, and she and Yun Tianqing discovered the clues and wanted to stop all this, so they withdrew when casting the spell.
But later, the two went to Qingluan Peak and gave birth to Yuntianhe, and after the host Shuyu died, Wangshu Jian also sealed the sword. It stands to reason that Yun Tianhe is the only flesh and blood of Shuyu, and it is reasonable that he is the next host of Wangshu Sword.
However, the Wangshu Sword will not harm the host, but Yun Tianhe was stabbed into the chest by the Wangshu Sword during the fight, indicating that Yun Tianhe is not the real Wangshu Sword host. So, who is the host of Wangshu Sword? Yun Tianhe is not the host, so why can he hold the Wangshu Sword in his hand?
This is going to start from when Yun Tianhe and Han Lingsha met for the first time.
At that time, in order to help her employer get the Wangshu Sword, Han Lingsha came to Qingluan Peak, and sneaked into the tomb of Yun Tianhe's parents
It wasn't until Lingsha and Tianhe held the Wangshu Sword together that the sword light of the Wangshu Sword soared into the sky and finally reappeared.
Due to the very strong cold aura of the Wangshu Sword's sword body, only Tianhe could hold the Wangshu Sword, while when others held the Wangshu Sword, their palms would freeze directly. Therefore, everyone naturally thinks that Tianhe is the host of Wangshu Sword. But that's not the case.
The reason why Tianhe was able not to be injured by Wangshu Jian's cold was because he inherited his mother's Yin and Cold body, and her mother had taken Yang Que before giving birth to him, and Yang Que crossed to Tianhe during her childbirth, so Tianhe was born cold and heat resistant and would not be injured by the cold. 
And the real host of Wangshu Sword is actually Han Lingsha. Tianhe has been practicing martial arts with the Wangshu Sword since he was a child, but the Wangshu Sword never reacted, and it was not until the moment Han Lingsha held the Wangshu Sword that the Wangshu Sword had a sense and appeared again.
The host of Wangshu Sword needs to be the body of the Yin and Cold, and Han Lingsha is the rare body of the Yin and Cold.
The reason why Han Lingsha couldn't hold the Wangshu Sword was because when she touched the Wangshu Sword, the Wangshu Sword would absorb her energy, and she would feel dizzy and even faint directly. In general, the host of Wangshu Sword needs to be the body of Yin and Cold, and after the death of the previous host, Wangshu Sword fell into a deep sleep, and it was not until Han Lingsha touched it that it recognized its master again.
And the Wangshu Sword will absorb the host's energy, so Han Lingsha will be dizzy when she touches the Wangshu Sword, and Yun Tianhe is not a real host, and he is born with cold and heat resistance because of his mother's physique, so he can hold the Wangshu Sword.